Eraser mounting



Aug. 2, 1949. 1.. J. MOST 2,478,123

ERASER MOUNTING Filed July 8, 1947 atented Aug. 2, 1949 STATES OFFICE 5 Claims.

My invention relates to eraser mountings and is an improvement over my United States Patent #2261127.

The object of th invention is to utilize the lateral resiliency of the rubber eraser for providing the necessary pressure to maintain a proper frictional engagement between the cap for the eraser and the mounting for the same.

Another object of the inventionis to provide a simple, inexpensive, and efficient eraser mounting by means of which wear of the rubber eraser can be easily compensated.

A further object of the invention is to provide an eraser mounting in which the lateral resilient pressure of the rubber eraser may be varied and thereby compensate for wear and tear taking place within the cap due to the frequent removal of the cap for the use of the eraser.

In the appended drawing forming part of this application,

Figure 1 is a fragmental section on line l-I, Figure 2, of a barrel end of either pencil or eraser.

Figure 2 is a cross-section on line 22, Figure 1.

Figure 3 is a similar section on line 3-3, Figure l, with the eraser not being in section.

Figure 4 is a part elevation and part section of the spring collet and its extension on line 44, Figure 6.

Figure 5 is a bottom end elevation of the spring collet and Figure 6 is a top end elevation of same.

Referring to the drawing, I is a fragmentary end of a barrel of either a pencil or an eraser. It is provided with a suitable bore H, at the end of which a flaring taper I2 is formed. At a distance from the flaring end within the bore H, a threaded portion i3 is provided. Fitting into the barrel end is a spring collet l4, having an exteriorly threaded end I and an outer taper I6 spaced from the threaded end I5 in the same relation as the threaded portion l3 of the barrel is with the flared taper i2. A tubular extension ll arises from the large end of the taper I6 of the collet, and it is oo-axial with the bore 20 of the collet, and its inner diameter is preferably of the same size as that of the bore 20.

The outer diameter of the tubular extension W is preferably reduced with reference to the large end of the taper It for two reasons; first, to obtain sufiicient wall thickness for the cap 23 that is to fit on the extension; second, to render the extension I! laterally yielding independent of the spring collet, of which the extension is an integral part. As a result of the reduction of the exterior diameter of the tubular extension, shoulder 24 is formed at the larger end of the taper 16.

The lateral outer surface of I! is preferably milled as indicated at IE to facilitate manipulation or the collet in the barrel end. The collet is provided with customary slits I 9, of which four are shown, the slits being extended through extension II, which results in the formation of four prongs flexing laterally. The interior bore 20 of the collet is of a diameter to permit easy sliding of a rubber eraser 2|.

To increase the gripping engagement of the collet with the eraser, circular grooves 22 are provided in the upper portion of the extension II. This arrangement causes the compressed rubber of the eraser at the grooves to enter thereinto and prevent any longitudinal movement of the eraser in the collet when undue pressure is applied in erasing. The grooves 22 are only one form of gripping means; others can be used as well.

In view of the wall thinness of the tubular extension I'l, .023, for a length of .250", the prongs formed by the slits [9 will flex laterally independent of the collets position in the barrel.

With an eraser within the collet, as shown in Figure 1, the lateral compression may be varied by moving the collet in the bore of the barrel. To reduce it, it is only necessary to release the pressure on the taper by unscrewing the collet, and the eraser may be moved along the collet as the case may be.

In cases where cap 23 becomes loose on the extension l! of the collet, the friction between the two may be increased by slightly reducing the pressure of the collet on the eraser by unscrewing the same slightly within the barrel. In consequence the eraser causes the extension I! to expand and thereby increase its frictional engagement with the milled part of the exten- 81011.

It is to be marked that the milling part on the extension serves two purposes, to facilitate the manipulation of the collet in the barrel and also to provide an adjustable frictional surface for the engagement of same with the cap 23.

By providing an eraser mounting as described, I provide an adjustable means for the eraser, and in addition an adjustable frictional engagement between the cap and the extension of the collet, which forms four prongs above the collet.

Where the eraser is to be exposed permanently, the cap is eliminated.

I claim:

1. An eraser structure comprising a barrel, a spring collet, said barrel and collet having cooperative means for varying the size of the bore of the collet, and a compressible rubber eraser fitted into the collet and extending into the barrel, said collet having a laterally yielding extension forming an integral part of the collet and extending therefrom out of the barrel, the said rubber eraser passing out of the extension.

2. An eraser structure comprising a barrel, a spring collet, said barrel and collet having cooperating means for causing the collet to grip or release an eraser within its bore, a rubber eraser fitted into the collet to be gripped by it when the collet is secured within the barrel, and a yielding extension from the collet co-axial therewith and adapted to project out of the barrel when the collet is fitted thereinto, said extension having depressed areas for increasing the gripping eiiect upon the rubber and a cap fitted frictionally on to the outer periphery of the extension.

3. In an eraser structure, the combination of, a barrel, a spring collet positioned at an end thereof, said collet and barrel having cooperative threads and tapers whereby the pressure of the collet on an eraser within it can be varied, a laterally yielding tubular extension rising from the collet at the taper part thereof, said tubular member being co-axial with the collet and provided with a milled outer surface, whereby the collet may be manipulated within the barrel to vary the pressure on an eraser Within the collet, a laterally compressible rubber eraser extending from the collet into the barrel and out of the tubular extension, said tubular extension having depressions on the inner surface thereof at predeterminate places and a cap fitted frictionally to the milled surface of the extension.

4. In an eraser structure, a barrel having a flared taper at the end, a threaded portion within the bore below the taper and spaced from same, a spring collet having an outer taper and an outer threaded end spaced from the collet's taper and in cooperative engagement with the taper and thread of the barrel, a compressible rubber eraser fitted into the collet and extending into the barrel, said collet having laterally yielding prongs extending from the taper out of the barrel and engaging the eraser within, the

said rubber eraser passing out of the said extension and a cap fitted frictionally to the prongs.

5. As an article of manufacture, a spring collet for gripping laterally compressible rubber erasers, comprising an exteriorly threaded end, an outer taper spaced from the threaded end and a plurality of laterally flexing prongs arising from the taper for engaging an eraser passing through the collet.

LUCIFER J MOST.

REFERENCES CITED The following referenices are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,123,339 Misuraca July 12, 1938 2,343,237 McElroy et a1. Mar. 7, 1944 FOREIGN PATENTS Number Country Date 361,917 Germany Oct. 30, 1922 

